1. Field of the Invention
The present invention relates to an image scanner, and more particularly to a compact image scanner which includes a flat-bed-type document scanning mechanism and an automatic-paper-feed-type document scanning mechanism.
2. Description of the Related Art
Image scanners for reading images on documents can be divided into three types; i.e., a flat-bed-type document scanner in which an image is read from a document placed on a glass platen, through movement of a line image sensor; an automatic-paper-feed-type document scanner in which documents stacked in a hopper are pulled out and transferred a single sheet at a time, and an image is read from each sheet by use of a fixed line image sensor; and an image scanner which provides functions corresponding to those of the flat-bed-type document scanner and the automatic-paper-feed-type document scanner (herein after this image scanner may be referred to as a xe2x80x9cdual-function image scannerxe2x80x9d).
Due to the necessity of providing two functions, such a dual-function image scanner involves a drawback of an increased size. Therefore, in order to enhance the utility of such an image scanner, a technique for realizing a compact image scanner must be developed.
A conventional dual-function image scanner has a structure as shown in FIG. 17.
That is, the conventional image scanner 1 provides two separate image-scanner functions; i.e., a function corresponding to that of a flat-bed-type document scanner for reading a document which is placed on a glass platen 2, and a function corresponding to that of an automatic-paper-feed-type document scanner for picking documents from a hopper 3 one sheet at a time and reading each sheet while transporting it to a stacker 4. In the image scanner 1, the hopper 3 is disposed above the glass platen 2, and the stacker 4 is disposed to project from the apparatus body.
The hopper 3 is removably attached to the apparatus body. When the image scanner 1 is used as a flat-bed-type document scanner, the hopper 3 is removed from the apparatus body. Alternatively, the hopper 3 may be hingedly attached to the apparatus body. In this case, when the image scanner 1 is used as a flat-bed-type document scanner, the hopper 3 is swung to a position at which the hopper 3 does not cause interference. In this state, a document placed on the glass platen 2 is read.
The conventional image scanner 1 having the above-described overall structure has an internal structure as shown in FIG. 18. That is, an optical unit 5 of the flat-bed-type document scanner is moved to a read position of an automatic-paper-feed-type document scanner in order to read the front face of a document. At the same time, the reverse face of the document is read by use of an optical unit 6, which is provided separately from the optical unit 5 and which is fixedly disposed at the read position of the automatic-paper-feed-type document scanner. In FIG. 18, reference numeral 11A denotes a document holding cover.
However, the image scanner 1 employing a conventional structure has a drawback of an increased size, because the stacker 4 is disposed to project from the apparatus body. In an exemplary case in which A4 documents are read along their longitudinal direction, since the length of A4 documents is about 300 mm, the stacker 4 projecting from the apparatus body must have a length of about 300 mm, resulting in an increase in apparatus size.
Further, the optical unit 5 provided in the flat-bed-type document scanner is used as an optical unit for the automatic-paper-feed-type document scanner. Therefore, the image scanner 1 has a relatively large length. That is, as shown in FIG. 19, when the flat-bed-type document scanner reads a document on the glass platen 2, the optical unit 5 of the flat-bed-type document scanner moves between the start point S and the end point E of a movement range MR. Further, when the optical unit 5 serves as an optical unit for the automatic-paper-feed-type document scanner, as indicated by a dotted line in FIG. 19, the optical unit 5 moves to a position F, at which the optical unit 5 reads the front face of a document while serving as the optical unit for the automatic-paper-feed-type document scanner. The position F is located below the position B, at which the optical unit 6 of the automatic paper-feed-type document scanner reads the reverse face of the document. Accordingly, the optical unit 5 must move to the read portion F of the automatic-paper-feed-type document scanner, thus increasing the length of the apparatus.
In view of the foregoing, an object of the present invention is to provide a compact improved image scanner which includes a flat-bed-type document scanning mechanism and an automatic-paper-feed-type document scanning mechanism.
According to one aspect of the present invention, there is provided an image scanner which comprises a flat-bed-type document scanning mechanism having a document holding cover; and an automatic-paper-feed-type document scanning mechanism disposed on the flat-bed-type document scanning mechanism and Discharging documents onto the document holding cover, wherein the document holding cover includes a groove and a stopper member fitted therein. The groove extends in the document transport direction and has a first engagement portion on its side wall. The stopper member has a base portion which has a second engagement portion that can be engaged with the first engagement portion and can be moved along the document transport direction while being guided by the groove, and a vertical portion projecting perpendicular from the base portion.
By virtue of the above-described structure, the stopper member can be inserted into and moved along the groove to thereby form a document receipt space on the document holding cover. Thus, the document holding cover can be used as a stacker.
In contrast to the case of the conventional scanner in which a stacker for receiving transported documents must be disposed such that the stacker projects from the apparatus body, in the image scanner of the present invention, a hopper for stacking document to be read is disposed to project from the apparatus body. The hopper can be disposed at a larger slant angle than can the stacker of the conventional scanner. Therefore, the size of the apparatus can be decreased greatly as compared with the case of the conventional scanner.
According to another aspect of the invention, there is provided an image scanner which comprises a flat-bed-type document scanning mechanism having a document holding cover; and an automatic-paper-feed-type document scanning mechanism disposed on the flat-bed-type document scanning mechanism and discharging documents onto the document holding cover, wherein an end of the document holding cover serves as a document-receipt-side end and has a concave shape concavely curved toward the document transport direction.
The image scanner according to the present aspect has the following additional advantage.
Since the document-receipt-side end of the document holding cover has a concave concavely curved toward the document transport direction, the document holding cover can reliably receive documents transported from the automatic-paper-feed-type document scanning mechanism. Therefore, the document holding cover can be used as a location to which documents are transported.
According to still another aspect of the present invention, there is provided an image scanner which comprises a flat-bed-type document scanning mechanism having a document holding cover; an automatic-paper-feed-type document scanning mechanism; arm members provided at an end portion of the document holding cover and being projected outward and upward, each of the arm members having a through-hole at its distal end; rotary shaft members, each having a slider portion, and a cylindrical portion which projects from the slider portion and is rotatably inserted into the through-hole of the corresponding arm member; and a cover member for covering the joint portion between the two document scanning mechanisms, the cover member having first cut-out spaces which extend vertically and accommodate the arm members, and second cut-out spaces which extend vertically and accommodate the rotary shaft members.
The cylindrical portions of the rotary shaft members are inserted into the through-holes of the arm members, and the rotary shaft members are then inserted into the cut-out spaces of the connection cover for covering the joint potion between the flat-bed-type document scanning mechanism and the automatic-paper-feed-type document scanning mechanism. Thus, opening/closing operation of the document holding cover is enabled.
The image scanner according to the present aspect has the following advantage in addition to the advantage of size reduction.
This structure enables the document holding cover to be used as a location to which documents are transferred, and further enables the flat-bed-type document scanning mechanism to read a thick document such as a book.
According to still another aspect of the present invention, there is provided an image scanner which comprises a flat-bed-type document scanning mechanism having a document holding cover and an optical unit; and an automatic-paper-feed-type document scanning mechanism disposed on the flat-bed-type document scanning mechanism and discharging documents onto the document holding cover, wherein the automatic-paper-feed-type document scanning mechanism has a first optical unit for reading a front face of a document and a second optical unit for reading a reverse face of the document, provided independently of an optical unit of the flat-bed-type document scanning mechanism.
The image scanner according to the present aspect has the following advantage in addition to the advantage of size reduction.
The above structure eliminates the necessity of moving the optical unit of the flat-bed-type document scanning mechanism to the read position of the automatic-paper-feed-type document scanning mechanism. Therefore, the length of the image scanner can be reduced as compared with the conventional scanner.